Figure 5. Cryo-SEM images as a function of WOin the microemulsion with lignin at fixed RP/W value of
4.78 with different WO value (wt. %) of (A) 9.2,
(B) 13.3, (C) 20.9, and (D) without lignin in (A).
Hence, it suggests that lignin macromolecules are able to facilitate the
formation of bigger and discrete microemulsion droplets, and then to
have this SFME system stabilized due to the aggregation of amphipathic
lignin at the surface of the microemulsion droplets, which can improve
the contact between lignin and hydrosoluble catalyst for the following
lignin oxidation. Additionally, by comparison the microemulsion droplets
with and without lignin, the size distribution of the former is less
concentrated than that of the later (Figure S3C), which can be
attributed to the high dispersion degree of lignin macromolecule (Table
S1), resulting a wider size distribution of droplets in the
microemulsion with lignin.